Method and system for treating different waste streams

ABSTRACT

Method and system for treating a waste stream. The waste is presented in containers, such as chamber pots and other containers for liquid and other kinds of waste. such waste can be supplied at different locations and is immediately comminuted. In a separating stage, the waste stream is separated into container material and actual waste. Actual waste is fed to a bioreactor where the water is purified so that it may be re-used, if desired. If biodegradable, the container material may be subjected to a fermentation step. Heat and gases released in the process may be used for heating the fermenter and/or generating power. It is also possible to feed kitchen waste, which may optionally have been comminuted, to the fermentation. The stream leaving the fermentation may be separated into hard components which are filtered off and composted and into softer components which can be fed to the purification installation.

The present invention relates to a method for treating a number ofdifferent waste streams in a care institution, such as a hospital, homefor the elderly, nursing home and the like. The invention also relatesto a system for treating a number of different waste streams in a careinstitution.

Such waste streams may comprise many different kinds of materials. Themost elementary are urine and feces which are collected in chamber potsand urinals. It is customary to deposit the urine and feces in a toiletbowl and dispose of them via the public sewage system, following whichthese will be discharged to the surface water, optionally afterpurification treatment in a purification installation for public sewagewater (RWZI). This has the drawback that the chamber pots and urinalshave to be cleaned separately, which is expensive and labor-intensiveand, in addition, increases the risk of contamination. A second drawbackis the fact that any medicinal and/or toxic substances contained in theurine and/or feces may end up in the surface water.

In order to overcome the first drawback, American document U.S. Pat. No.6,351,858 B1 discloses a process to collect feces and urine incontainers and to gather these containers together with their content.The containers are placed on a trolley and taken to a comminutingmachine. The comminuting machine then comminutes the containers(together with their contents) with the addition of a homogenizingliquid, such as water. The combination is discharged to the publicsewage system, optionally after having been filtered. Although the knownprocess may have a positive effect on hygiene in the care institution,the abovementioned second drawback of the possible release of medicinaland/or toxic substances into the environment is not overcome. Inaddition, the known process still requires the containers to becollected and the collected containers to be physically moved by meansof a transport vehicle to a comminuting apparatus which is locatedinside the building of the care institution.

However, there are more waste streams which have to be treated in a careinstitution. A further waste stream is formed by kitchen waste. Thiskitchen waste is generally not contaminated, that is to say does notcontain medicinal and/or toxic substances which are harmful to theenvironment, and can be taken to a dump in garbage bags or to anindustrial composting plant in containers for vegetable, fruit andgarden waste. Collecting kitchen waste, putting it into garbage bags orinto containers for vegetable, fruit and garden waste and transportingthe garbage bags to a dump or industrial composting plant using trucksis expensive and labor-intensive.

A further waste stream consists of waste water which originates fromdepartments in the care institution which use water, for example bathand/or shower water or water used in a kitchen, which is normallydischarged via the sewage system. However, such bath and/or shower wateris often polluted with medicinal and/or toxic substances, which, forexample, originate from patients' perspiration moisture. The sewagewater which is contaminated in this way can then pass into theenvironment without having been purified or at least not sufficientlypurified.

A further waste stream is formed by waste which is caused by thetreatment of patients, such as drugs, bandages, etcetera. Such waste ispotentially contaminated, that is to say that the waste contains arelatively high concentration of medicinal, bacterially and virallyinfectious material and/or toxic substances, and discharging such wasteuntreated has grave consequences. In the first place, the environmentwhere the waste is dumped suffers badly. If such waste reaches a sewagewater purification installation (RWZI), additional measures have to betaken in order to remove this waste. This would mean that the entirevolume of waste, also the less polluting components thereof have to betreated, which results in high costs. Therefore, in practice, this wasteis not discharged via the sewer system, but is discharged strictlyseparate from the other waste. Currently, specific hospital waste (SHW),also referred to by Eural code 18 of the European list of wastesubstances, has to be presented in special containers and disposed of inspecial incinerators suitable for incinerating hospital waste.

As has been explained above, the care institution produces differentwaste streams. Some waste streams are discharged via the usual sewagesystem and other waste streams are collected separately and dischargedvia separate procedures.

It is an object of the present invention to make the treatment of wastestreams more efficient, as a result of which the costs for careinstitutions can be reduced without compromising hygiene.

It is another object of the present invention to make the treatment ofwaste streams more hygienic.

Furthermore, it is an object to purify the quality of the waste waterfrom polluted, toxic, medicinal, bacterial, viral and/or hormonalsubstances as well as the other substances which are also purified by asewage water purification installation in such a manner that the qualityof the waste water is significantly improved and, if desired, is also ofsufficient quality for the purified water to be discharged into thesurface water.

At least one of these objects is achieved by the method for treating anumber of different waste streams by means of a local purificationsystem of a care institution, wherein the waste streams comprise atleast one first waste stream which comprises substantially feces andurine and a second waste stream which comprises substantially wasteplaced in a container and comprising medicinal and/or toxic substances,the method comprising:

-   -   discharging the first waste stream and the second waste stream        via pipes of a pipe system, the waste streams being fed to        respective pipes of the pipe system at different locations,    -   passing the waste streams through one or more comminuting        devices for comminuting the waste and the containers,    -   separating the actual waste and the container material from the        waste stream which is obtained in this manner,    -   feeding the actual waste to a purification installation and        purifying the liquid constituents present therein.

The purification system is local which means that it is provided in ornear the care institution, and may, in addition, be readily connected tothe public sewage system or to the surface water. The latter is possibleby virtue of the extremely low degree of pollution of the dischargestream produced by certain embodiments of the purification systemaccording to the invention.

The inventors have come to the surprising finding that it is readilypossible to jointly treat and purify two or more waste streams whichshould normally be kept strictly separate in care institutions. Once theinventors had arrived at this finding, it became clear that the jointtreatment of the waste streams has a large number of advantages. As, forexample, the first and second waste streams are passed through at leastone purification device which is the same for both waste streams and, insome embodiments, waste streams can also be passed through the samecomminuting devices, the costs for purifying the waste streams can bedramatically reduced.

The different waste streams can be introduced into the pipe systemseparately in order to be mixed with one another in it in a furtherstep. It is, for example, possible to carry out mixing directly at theinlet into the system, so that the comminuting treatment is carried outon the mixture of waste streams. In another embodiment, the wastestreams are first comminuted separately, for example by passing thewaste streams one after the other through the same comminuting device orby passing each of the waste streams through a separate comminutingdevice, in order only then to be mixed with one another. The subsequentseparating stage is then carried out on the mixture of the differentwaste streams. Depending on the type of waste stream, it is alsopossible to omit the comminuting step. When processing shower and/orbath water, for example, the comminuting step can be omitted.

In addition, according to the present invention, the container and theactual waste are no longer separated. That is to say, feces and/or urineare discharged together with the container (such as a chamber pot),which means that the costly handling of containers is made completelyredundant. The containers are made to be disposable. According to thepresent invention, it is possible to feed waste to a pipe system atdifferent locations, for example in each department.

As a first step, the first and second waste stream are comminuteddirectly at the inlet, so that the waste can be introduced into a pipesystem without any risks so that there is no fear of blockage.

Subsequently, the waste from different inlets is subjected to aseparating treatment, preferably at a central location. During thisseparating treatment, the container material is separated from theactual waste stream. The actual waste stream comprising urine, feces,drugs and the like is fed to a purification installation and, afterhaving been processed, purified water is obtained which may, if desired,be re-used, but can at least be discharged to the sewer system withoutcausing environmental damage. The purification installation may comprisea bio-membrane reactor, that is to say a reactor in which the liquidwhich is released is subjected to membrane filtration in order toguarantee purity. Any sludge which may have accumulated can bedischarged periodically. However, the amount of sludge is very small anddoes not cause substantial costs. Other purification techniques may alsobe used in addition to or instead of purification by means of abio-membrane reactor, which may, for example be based on filtration. Itis also possible to use a succession of several filter systems.

If the container material used substantially consists of plasticmaterial, the latter is cleaned following the comminuting and separatingtreatment and can be discharged in order to be re-used. The flushingwater which results from this process may be fed to the purificationinstallation.

If the container material contains biodegradable substances, such assubstances based on PLA, purification is preferably likewise carried outafter separation from the actual waste. In this case as well, flushingwater can be fed to the bioreactor. The resulting relatively clean PLAcan be subjected to a fermentation treatment in a fermenter. It is alsopossible to feed in waste streams from, for example, the kitchen of ahospital or the like. Such waste streams will likewise preferably becomminuted beforehand.

During fermentation, both solid/liquid material and gas are released.This gas can be used for heating purposes, for example for heating thefermenter and/or for generating power. The solid/liquid material ispreferably separated into hard components and non-hard components. Thehard components can be composted, while the non-hard components can befed to the inlet of the purification installation. Using the presentinvention, it is possible to process a stream of waste in a continuousmanner, while the resulting substances can generally be effectivelyre-used so that the processing of the latter does not entail high costs.Preferably, bio-membrane filtration, in particular ultrafiltration,nanofiltration, osmosis and/or hyperfiltration takes place in thepurification installation, followed by additional filtration techniques,such as oxidation, UV-filtration, active carbon filtration and the like.The purpose of this additional filtration is to remove substances, suchas for example heavy metals and/or toxic substances, which have not beenfiltered out by the membrane filters.

The invention also relates to a purification system of a careinstitution for treating a number of different waste streams, whereinthe waste streams comprise at least one first waste stream whichsubstantially comprises feces and urine and a second waste stream whichcomprises waste substantially placed in a container and comprisingmedicinal and/or toxic substances, the purification system comprising apipe system with a number of inlets which can be arranged at differentlocations in the care institution and which are connected to the outletsfor at least the first and second discharge stream, one or morecomminuting devices connected to each of the inlets via pipes forcomminuting the waste together with the containers from the dischargeflows, wherein the outlets of the comminuting devices are connected to aseparating device for separating actual waste materials and containermaterials from the waste stream, a purification installation beingconnected to the outlet of the separating device for the actual wastematerial.

The invention will be explained below in more detail by means of twoexemplary embodiments, in which:

FIG. 1 diagrammatically shows a first variant of the invention for usewith non-biodegradable containers; and

FIG. 2 shows a variant of the invention for use with biodegradablecontainers.

In FIG. 1, reference numeral 1 denotes a first variant of the systemaccording to the present invention. Such a system is preferably used ina care institution or another establishment where intensive care ofpeople takes place used, such as a hospital, home for the elderly andthe like.

Waste is produced during caring, such as feces and the like, and this isdischarged together with the container thereof via inlets 2 located inthe various departments. A pipe system is connected to the inletsthrough which the waste can be transported. The term “pipe” is in thiscontext understood to mean any form of tube, shaft, duct, conduit, etc.A comminuting device 3 is situated directly downstream of the inlets 2.After comminution, the waste can readily be passed through a pipesystem. Preferably, a central separating device 4 is provided into whichthe different inlets debouch. In this separating device, the actualwaste (feces and the like) is separated from the containers, that is tosay the container material. The actual waste is fed to a purificationinstallation 5. The liquid material (water) which constitutes by far thelargest part is discharged at 15 following a further separation and maybe re-used, if desired. Incidentally, discharge to a sewer system doesnot cause any environmental damage so that no additional environmentallevies will have to be paid.

The stream of container material is passed to a purification device 6.The plastic material or other material is treated by means of a cleaningfluid, for example flushing water which may, for example, be theflushing water emanating from outlet 15. Subsequently, the flushingwater is separated from the treated material and this flushing water isreturned to the purification installation 5 via pipe 14. The treatedcontainer material is discharged via outlet 7 in order to be re-used.

In contrast to the prior art, the above method does not result in largeamounts of polluted waste which is very expensive to process.

FIG. 2 shows a variant of the present invention. In this case, thesystem is denoted overall by reference numeral 31 and waste is suppliedvia inlets 32. In contrast with the embodiment from FIG. 1, thecontainer portion of the waste comprises biodegradable types ofmaterial, such as paper-like types of material, biodegradable plastics,such as PLA plastics. These are comminuted in a comminuting device 33 inthe manner described above and centrally fed to a separating device 34where the actual waste stream is again separated from the containermaterial. The actual waste stream is fed to the purificationinstallation 35 and the water which is released in the process isdischarged via outlet 45 in order to be re-used.

The biodegradable material which is released in the separating device 34is initially treated in the manner described above in purificationdevice 36. The flushing water which is used and which may come fromoutlet 45 is again fed to the purification installation 35 in this caseas well. The treated container material is fed to a fermenter 38 bymeans of a pipe 37. It is also possible to feed kitchen waste to thisfermenter 38 by means of inlet 39 and a further comminuting device 40.

Fermentation in the fermenter 38 produces heat/gas, which heat/gas canbe used for heating the fermenter 38 and/or for generating power inorder to promote the degradation process and the conditions for themicro-organisms in the fermenter. The solid/liquid waste stream is fedto a separator 41 where the hard components are filtered out anddischarged in order to be composted 42. If desired, a heating step isalso carried out in order to render any bacteria in the hard componentsharmless by heating. The softer components including the liquid are fedto the purification installation via pipe 43.

The above variants show that many variants are possible based on theinventive idea. It is possible to add stages and/or to skip stages. Allthis is covered by the scope of the attached claims and rights areexpressly requested for the subject matter of the subclaims, separatefrom the main claim.

Above, reference has been made to a waste stream obtained by comminutinga container which contains waste. However, the device described is notlimited to treating only this type of waste stream. It is also possibleto carry water originating from showers, toilets, kitchens, denoted inFIG. 2 by reference numeral 47, along in the waste stream to be treated.Such a device is connected to the pipe system by means of the pipe 46.

Actually, all the water which is used in a care institution and whichhas, until now, been discharged in the sewage system, can be treated inthis manner. One of the examples which has already been mentioned isshower water. When a patient, whose body perspiration may containmedicinal or hormonal waste substances, or other harmful wastesubstances (such as chemotoxic agents), is being showered or showers,such substances end up in the shower water. These substances can thenlikewise be removed in the purification installation according to theinvention.

The present invention is not limited to the preferred embodimentsdescribed above. The scope of protection is determined by the scope ofthe following claims which allows for a great many modifications.

1. A method for treating a number of different waste streams by means ofa local purification system of a care institution, wherein the wastestreams comprise at least one first waste stream which comprisessubstantially feces and urine and a second waste stream which comprisessubstantially waste placed in a container and comprising medicinaland/or toxic substances, the method comprising: discharging the firstwaste stream and the second waste stream via pipes of a pipe system, thewaste streams being fed to respective pipes of the pipe system atdifferent locations, passing the waste streams through one or morecomminuting devices for comminuting the waste and the containers,separating the actual waste and the container material from the wastestream which is obtained in this manner, feeding the actual waste to apurification installation and purifying the liquid constituents presenttherein.
 2. The method as claimed in claim 1, comprising treating theseparated container material with a cleaning fluid, discharging thecleaning fluid to the purification installation and discharging theseparated and treated container material.
 3. The method as claimed inclaim 2, comprising fermenting the discharged and treated containermaterial in a fermenter.
 4. The method as claimed in claim 1, whereinthe waste stream also comprises a third waste stream substantiallycomprising shower and/or bath water.
 5. The method as claimed in claim1, wherein the waste stream also comprises a fourth waste streamsubstantially comprising food.
 6. The method as claimed in claim 1,wherein the different waste streams are fed into the pipe systemseparately and mixed with one another in the latter.
 7. The method asclaimed in claim 6, comprising first comminuting the first and secondwaste stream and then mixing the comminuted first and second wastestreams.
 8. The method as claimed in claim 7, comprising mixing thecomminuted first and second waste streams with a non-comminuted furtherwaste stream following comminution of the first and second waste stream.9. The method as claimed in claim 1, wherein said container comprises abiodegradable material and is fed to the purification installation. 10.The method as claimed in claim 9, wherein the biodegradable material ofsaid container is fermented prior to being fed to a purificationinstallation.
 11. The method as claimed in claim 10, also comprising thefermentation of the fourth waste stream.
 12. The method as claimed inclaim 3, wherein the heat produced during fermentation is used forheating the waste stream in the fermentation tank and/or the use ofgenerating power.
 13. The method as claimed in claim 3, wherein hardcomponents are removed from the waste stream produced duringfermentation which is fed to the purification installation.
 14. Themethod as claimed in claim 1, wherein the material of thenon-biodegradable substances in the waste is separated from the materialof the biodegradable substances after comminution, and wherein thebiodegradable substances are discharged separately from saidbioreactor/fermentation.
 15. The method as claimed in claim 1, whereinpurifying the liquid constituents of said waste stream comprisesmembrane filtration.
 16. A purification system (1, 31) of a careinstitution for treating a number of different waste streams, whereinthe waste streams comprise at least one first waste stream whichcomprises substantially feces and urine and a second waste stream whichcomprises substantially waste placed in a container and comprisingmedicinal and/or toxic substances, the purification system comprising: apipe system with a number of inlets (2, 32) which can be arranged atdifferent locations in the care institution and which are connected tothe outlets for at least the first and second discharge stream, one ormore comminuting devices (3, 33) connected to each of the inlets viapipes for comminuting the waste together with the containers from thedischarge flows, wherein the outlets of the comminuting devices areconnected to a separating device (4, 34) for separating actual wastematerials and container materials from the waste stream, a purificationinstallation (5, 35) being connected to the outlet of the separatingdevice (4, 34) for the actual waste material.
 17. The purificationsystem as claimed in claim 16, wherein the separating device comprises afurther outlet for discharging the container materials, which outlet isconnected to a purification device for treating the separated containermaterial with a cleaning fluid.
 18. The purification system as claimedin claim 17, wherein the purification device is provided with a firstdischarge for discharging the waste cleaning fluid to the purificationinstallation and a second discharge for discharging the separated andtreated container material.
 19. The purification system as claimed inclaim 16, wherein a fermenter (38) is connected to the second outlet ofthe separating device for the container materials.
 20. The purificationsystem as claimed in claim 19, wherein the fermenter comprises an inletfor a fourth waste stream substantially comprising food.
 21. Thepurification system as claimed in claim 16, wherein the pipe systemcomprises at least one further inlet (47) which is connected to awater-consuming device (46), in particular a shower and/or toilet and/orkitchen, for discharging a third waste stream.
 22. The purificationsystem as claimed in claim 16, wherein a liquid separator (41) having afirst outlet for discharging separated liquid and a second outlet fordischarging the remainder of the waste, is arranged in or downstream ofthe fermenter, and wherein the first outlet is connected to thepurification installation (35).